<div class="problemindexholder" problemindex="A">
 <div class="ttypography">
  <div class="problem-statement">
   <div class="header">
    <div class="title">
     A. ACM ICPC
    </div>
    <div class="time-limit">
     <div class="property-title">
      time limit per test
     </div>
     2 seconds
    </div>
    <div class="memory-limit">
     <div class="property-title">
      memory limit per test
     </div>
     256 megabytes
    </div>
    <div class="input-file">
     <div class="property-title">
      input
     </div>
     standard input
    </div>
    <div class="output-file">
     <div class="property-title">
      output
     </div>
     standard output
    </div>
   </div>
   <div>
    <p>
     In a small but very proud high school it was decided to win ACM ICPC. This goal requires to compose as many teams of three as possible, but since there were only
     <span class="tex-span">
      6
     </span>
     students who wished to participate, the decision was to build exactly two teams.
    </p>
    <p>
     After practice competition, participant number
     <span class="tex-span">
      <i>
       i
      </i>
     </span>
     got a
     <span class="tex-font-style-it">
      score
     </span>
     of
     <span class="tex-span">
      <i>
       a
      </i>
      <sub class="lower-index">
       <i>
        i
       </i>
      </sub>
     </span>
     .
     <span class="tex-font-style-it">
      Team score
     </span>
     is defined as sum of scores of its participants. High school management is interested if it's possible to build two teams with equal scores. Your task is to answer that question.
    </p>
   </div>
   <div class="input-specification">
    <div class="section-title">
     Input
    </div>
    <p>
     The single line contains six integers
     <span class="tex-span">
      <i>
       a
      </i>
      <sub class="lower-index">
       1
      </sub>
      , ...,
      <i>
       a
      </i>
      <sub class="lower-index">
       6
      </sub>
     </span>
     (
     <span class="tex-span">
      0 ≤
      <i>
       a
      </i>
      <sub class="lower-index">
       <i>
        i
       </i>
      </sub>
      ≤ 1000
     </span>
     ) — scores of the participants
    </p>
   </div>
   <div class="output-specification">
    <div class="section-title">
     Output
    </div>
    <p>
     Print "
     <span class="tex-font-style-tt">
      YES
     </span>
     " (quotes for clarity), if it is possible to build teams with equal score, and "
     <span class="tex-font-style-tt">
      NO
     </span>
     " otherwise.
    </p>
    <p>
     You can print each character either upper- or lowercase ("
     <span class="tex-font-style-tt">
      YeS
     </span>
     " and "
     <span class="tex-font-style-tt">
      yes
     </span>
     " are valid when the answer is "
     <span class="tex-font-style-tt">
      YES
     </span>
     ").
    </p>
   </div>
   <div class="sample-tests">
    <div class="section-title">
     Examples
    </div>
    <div class="sample-test">
     <div class="input">
      <div class="title">
       Input
      </div>
      <pre>1 3 2 1 2 1<br/></pre>
     </div>
     <div class="output">
      <div class="title">
       Output
      </div>
      <pre>YES<br/></pre>
     </div>
     <div class="input">
      <div class="title">
       Input
      </div>
      <pre>1 1 1 1 1 99<br/></pre>
     </div>
     <div class="output">
      <div class="title">
       Output
      </div>
      <pre>NO<br/></pre>
     </div>
    </div>
   </div>
   <div class="note">
    <div class="section-title">
     Note
    </div>
    <p>
     In the first sample, first team can be composed of
     <span class="tex-span">
      1
     </span>
     st,
     <span class="tex-span">
      2
     </span>
     nd and
     <span class="tex-span">
      6
     </span>
     th participant, second — of
     <span class="tex-span">
      3
     </span>
     rd,
     <span class="tex-span">
      4
     </span>
     th and
     <span class="tex-span">
      5
     </span>
     th: team scores are
     <span class="tex-span">
      1 + 3 + 1 = 2 + 1 + 2 = 5
     </span>
     .
    </p>
    <p>
     In the second sample, score of participant number
     <span class="tex-span">
      6
     </span>
     is too high: his team score will be definitely greater.
    </p>
   </div>
  </div>
  <p>
  </p>
 </div>
</div>
